Guys,

I have been trying to find out what is causing the "light bulb out" warning on the panel to be on. Have checked all outside lights and all are working. Pulled both tail light assemblies out to compare left to right. They both functioned the same. However there is one bulb on both sides that doesn't light up on either side regardless as to what command I give it. Reverse, brakes, turn signals, bright or low. This bulb is the most inboard on the bottom row of three bulbs. Have checked the bulb on each side and both are good.

I am very confused. Any help would be greatly appreciated.

 

Fuse # 1 / 10 amp LH Heelbord use box called rear fog .

 

Those are the "rear fog light" bulbs. The switch is on the left side dash next to the front fog light switch. The rear fogs are bright like brake lights. Not really used in the US. The bulb fail warning won't be activated unless you turned them on and one was burned out. Although I'm not quite sure about that, I'll have to test it.

However, I recently discovered that a failed side marker lamp (at least on the earlier builds like yours and mine) will light up the bulb fail warning. Did you check those 4 too?

 

The light bulb out monitor is a current sensor inside the lamp control module . If you have the wrong bulb in that is a higher resistant bulb in it would limit the current and trip the monitor . The bulb listed in the vehicle care book on page 69 is 21 watt

 

Results are in. The bulb fail warning WILL light for the rear fog lights, if one of the bulbs is out when you switch them on. Neat.

 

Check the number plate lights as well as they are monitored.

 

Yep. Key info: the bulb out monitor is monitoring bulbs that are supposed to be "on."
So if you only see it when you press the brake pedal....you've got a brake light out. If it lights as soon as you turn the running lights on...time for a careful walkaround to see what's what. As Richard observed, it monitors front and rear fogs, but only when they are switched on.
So you can narrow down the possibilities somewhat from the comfort of your leather-clad chair in the cockpit by playing with the switches and pedals. I guess I've not yet had a failed turn indicator, cause I can't recall a blinking bulb out indicator.

 

FINALLY FINALLY FOUND THE BURNED OUT BULB. Thanks for everyone that responded with some good ideas, but not the right ones. Oh? You want to know the bad burned out bulb?? It was one of the license plate bulbs. When you do a walk around you don't see it under the trunk handle. Replaced it and the #$%^ orange indicator light, third from the top on the left side Stayed out. Hurray!

Thanks guys

 

Did you read post no 6?

 

This thread is funny stuff. To top off this vast body of bulb-fail knowledge, know that if a turn signal bulb goes out, the bulb fail indicator will light steadily, but only when the turn signal is engaged. At the same time, the turn signal will flash at twice its normal rate.

Honorable mention to Robman25 who correctly "diagnosed" EZDriver's problem from afar.

 

Thanks to all. It has been fun and informative. I'll see if I can find something that goes wrong.

No, I didn't read post #6 nor did I read it before I posted my success. I was at the airport hangar working on both Jags that day. Got a coil out on the XK8. But I would have found if I hadn't lucked out. Good work Robman

Thanks again guys. We'll do it again sometime.

 

Worth a caution: The errant number plate bulb EZDriver found can be a mystery on some cars. The lens-casings tend to overheat and fall off...and then the bulb-holder and bulb retreat up into the bootlid but behind the fabric finishing. All that is well and good until the bulb burns out. Then you see the asymetrical lighting on the number plate...but you don't find a burnt bulb unless you go exploring. However, BOTH number plate bulbs can retreat into the bootlid as well and then you are just wandering 'round the car looking for an unlit bulb and perhaps wondering to yourself why a premium motorcar company such as Jaguar would not have seen fit to light the rear number plate on their flagship model...

 

I have solved my problem as I found the license plate bulb out as described above. But I have a friend that has a 97 XJ6 with the dash warning light on. We both have searched the car and cannot find any light that is not on that should be on. Including license plate, bright and normal head lights, back up, both turn signals, fog lights..... any other suggestions??? I promised him I would ask you guys for help. I sure wasn't much good.

 

You might have him go through it regarding post #4 from Parker, above. In addition to that, I seem to recall reading in here somewhere that it compares current draw between similar bulbs, side-to-side. Maybe check that each pair are same p/n bulb before worrying about whether each and every bulb is identical to the original spec. Another key is when the monitor is lit? as soon as position lights are turned on? As noted above, with the exception of turn indicators, the monitor will only light up when the problem bulb is supposed to be on and isn't....or at least isn't acting in accordance with what the monitor expects.